Electrical connector



J. R. KELLER Nov. 28, 1967 ELECTRICAL CONNECTOR 4 Sheets-Sheet 1 FiledApril 28, 1965 Nov. 28, 1967 J. R. KELLER 3,355,698

' ELECTRICAL CONNECTOR Filed April 28, 1965 4 Sheets-Sheet 2 i k N".

l 6 p I N d INVENTOR, \tfgml? JOSEPH 'Rlcmwu KELLER BY W, W 1 74 J- R.KELLER Nov. 28, 1967 ELECTRICAL CONNECTOR 4 Sheets-Sheet 5 Filed April28, 1965 RL 5 M m N I H J. R. KELLER Nov. 28, 1967 ELECTRICAL CONNECTOR4 Sheets-Sheet 4 Filed April 28, 1965 M/I/I/l/l/ m R m m V M v R HI P I!S M J Y B United States Patent G ice 3,355,698 ELECTRICAL CONNECTORJoseph Richard Keller, Harrisburg, Pa., assiguor to AMP Incorporated,Harrisburg, Pa. Filed Apr. 28, 1965, Ser. No. 451,394

13 Claims. (Cl. 339-97) This invention relates to electrical connectorsand more particularly to electrical connectors of the type crimpableonto conductor means.

An object of the invention is to provide an electrical connector that iscrimpable onto the conductive portion of conductive means.

Another object of the invention is the provision of an electricalconnector having ribs disposed transversely to the direction of the axisof the electrical connector.

A further object of the invention is to provide an electrical connectorhaving ribs that can take various forms.

An additional object of the invention is the provision of an electricalconnector having ribs extending outwardly from an interior surface andinsulation disposed on an exterior surface.

A still further object of the invention is to provide a pre-insulatedconnector for engaging the conductive portion of conductive means.

Still another object of the invention is the provision of apro-insulated connector having transverse ribs or pressure-relievingmeans for engaging the conductive portion of conductive means.

Other objects and attainments of the present invention will .becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there is shown and described illustrative embodiments of theinvention; it is to be understood, however, that these embodiments arenot intended to be exhaustive nor limiting of the invention but aregiven for purposes of illustration in order that others skilled in theart may fully understand the invention and the principles thereof andthe manner of applying it in practical use so that they may modify it invarious forms, each as may be best suited to the conditions of aparticular use.

The foregoing objects are achieved in the present invention through theprovision of an electrical connector means having a U-shaped metalmember provided with rib members extending outwardly from the insidesurface of the U-shaped member and transverse to the axis thereof.Insulation means is disposed on the exterior surface of the U-shapedmember. The connector means is crimpable onto insulated conductor meansfor electrical and me chanical engagement with the conductive portion ofthe conductor means.

In the drawings:

FIGURE 1 is a perspective view of connector means in feed strip form;

FIGURE 2 is a perspective view partially in section of the connectormeans of the present invention;

FIGURES 3 through 11 are cross sectional views of the metallic portionof the connector means illustrating various forms of the rib membersextending outwardly from the surface thereof;

FIGURES l2 and 13 are perspective views of the connector means crimpedonto conductor means;

FIGURE 14 is a view taken along lines 1414 of FIGURE 13;

FIGURE 15 is a view taken along lines 1515 of FIGURE 13;

FIGURES l6 and 17 are perspective views of the connector means crimpedonto conductor means;

FIGURE 18 is a cross sectional view of the connector means crimped ontoconductor means;

3,355,698 Patented Nov. 28, 1967 FIGURE 19 is a perspective explodedview of an embodiment of the present invention;

FIGURE 20 is a perspective view of the connector means in FIGURE 19 inits crimped condition onto a conductor means;

FIGURE 21 is a view taken along lines 21-21 of FIGURE 20;

FIGURE 21:: is a view similar to FIGURE 21 except that the rib membersdo not extend to the ends of the sides of the metallic member;

FIGURE 22 is a longitudinal sectional view of FIG- URE 20;

FIGURE 23 is a view similar to FIGURE 22 but is directed to anotherembodiment;

FIGURE 24 is a perspective View of a further embodiment of the presentinvention;

FIGURE 25 is a longitudinal cross-sectional View of FIGURE 24;

FIGURE 26 is a perspective view of the embodiment of FIGURES 24 and 25in its crimped condition;

FIGURE 27 is a view taken along lines 2727 of FIGURE 25;

FIGURE 28 is a view taken along lines 28-28 of FIGURE 26; and

FIGURE 29 is a view taken along lines 29-29 of FIGURE 26.

Turning now to the drawings, there is illustrated a series of connectormeans CM integrally connected to slotted feed strip members 1 viainsulation 2 of the connector means. Connector means CM, in feed stripform as illustrated in FIGURE 1, are appropriately fed into a crimpingarea of an applicator completely disclosed in Set. Number 451,601 filedApr. 28, 1965, now Patent No. 3,292,236 and assigned to the presentassignee for successively crimping the connector means onto con-. ductormeans. Of course, the connector means may be fed into the crimping areaof a crimping machine or crimping tool in any suitable manner as well asbeing individually placed within the crimping areas of a crimpingmachine or crimping tool.

Connector means CM comprises a metallic member 3, formed into a U-shapehaving rib members 4 extending outwardly from the interior surfacethereof. The rib members extend transversely with respect to the axis ofU- shaped metallic sheet 3; the rib members are preferably spaced fromeach other with the rib members covering about half the length ofmetallic member 3. As can be discerned, the portions of metallic member3 from the outermost rib members 4 to each end of metallic member 3contain no rib members so that the rib members are disposed inwardlyfrom each end of the metallic member.

As can be perceived from FIGURES 3 through 11, rib members 4 takevarious forms. The rib members in FIGURE 3 are of the same height andare rectangular shaped in cross section. In FIGURE 4, the thickness ofmetallic member 3 between rib members 4 is less than that of theoutermost portions beyond the rib members. Rib members 4 in FIGURE 5 areof the same height and have a wedge shape in cross section. The ribmembers in FIGURE 6 are similar to those in FIGURE 5 except that thetops are rounded. Likewise in FIGURE 7, rib members 4 are similar tothose of FIGURE 5 except that the top of each rib member is providedwith sharp edges. Rib members 4 in the embodiment of FIGURE 8 increasein height from outermost rib members 4 to the center, while in FIGURE 9,the rib members increase in height from the center to the outermost ribmembers. The rib members in FIGURE 10 are a combination of the ribmembers of FIGURES 6 and7. In FIGURE 11, the rib members are ofalternate heights. The thin p01 tion of metallic member 3 between ribmembers 4 as illustrated in FIGURE 4 can of course be applied to theother embodiments. While there have been disclosed variousconfigurations of rib members 4, other configurations of rib memberscan, of course, be utilized as well as combinations thereof. It is alsoto be understood that the number of rib members extending outwardly fromthe interior surface of the sheet metal member depends upon many factorssuch as, for example, the length of the connector member, the distancebetween rib members, the thickness of the rib members, etc. The heightof the rib members is determined by the type of conductor means to beterminated.

A suitable insulation material 2 is disposed on the exterior surface ofU-shaped metallic member 3 and is preferably adhered thereto by means ofa suitable adhering substance. As can be discerned from FIGURES l and 2,insulation 2 extends outwardly from the ends and sides of metallicmember 3. The insulation material for use in conjunction with thepresent invention must be yieldable, must have a good coefficient offriction relative to the crimping members and must be tough. It has beenfound that Mylar fulfills the foregoing requirements and is thereforethe insulation material that is preferably used in conjunction with thepresent invention; however, any other material fulfilling the foregoingrequirements may be used. Insulation material 2 is preferably inlaminated form with two sheets of Mylar glued together by means of arubber based glue.

One reason for laminating the insulation material is to obviate anypossibility of the insulation material having any discrepancy since anydiscrepancy occurring in the insulation material precludes the connectormeans from performing its intended function of providing a preinsulatedconnector means for terminating conductor means. Therefore, in the eventthat one of the thin sheets of laminated plastic has a discrepancytherein, it is an extreme remote possibility that the other thin sheetof plastic material will have a discrepancy at the same location;whereas, if the insulation material was nonlaminated and comprised asingle sheet of material of equal thickness as that of the laminatedmaterial, a discrepancy occuring in this single sheet of insulationmaterial would impair the insulation properties of the connection whenthe connector means is crimped onto a conductor means. Another reasonfor laminating the insulation material is that the rubber based glueallows the insulation material to flow more evenly with the metallicmember during formation of the preinsulated connector means and duringthe crimping operation of the conector means onto the conductor means.Thus, the inside sheet of the laminated insulation material may beimpaired during the crimping operation but the outside sheet of theinsulation material will not be impaired at the location of impairmentof the inside sheet thereby providing an insulated connection which ishighly reliable. If a single sheet of insulation material is used inplace of the laminated insulation material and if the single sheet ofinsulation material is impaired during the crimping operation, thisimpairs the insulation properties of the connection thereby decreasingits reliability.

The following procedure sets forth the desirable mode for manufacturingthe connector means in strip form as illustrated in FIGURE 1. A strip ofmetal such as, for example, brass is subjected to a milling operation toform a strip of ribbed material. Of course, the strip of metal can alsobe subjected to a rolling, skiving, extruding or any other suitableoperation to form a strip of ribbed material. A profiling operation isperformed on the strip of ribbed material by conventional tooling toform the profile of metallic member 3 in its desired form. Insulationmeans 2 is formed as a laminated structure by gluing two thin sheets ofinsulation material such as, for example, Mylar together to form a stripof insulation-material about twice the width of the metallic strip ofribbed material. The laminated strip of insulation material is adheredto the metallic strip of ribbed material with the strip of ribbedmaterial disposed centrally of the strip of insulation material. Thecombined strip of metallic ribbed material and insulation material isprofiled by conventional tooling to form the sides of the insulationmaterial into slotted feed strip members and the profiled metallicmembers along with the insulation material are formed into U-shapedconnector means with the ends of insulation 2 being connected to feedstrip members 1 via portions 5. Thus, there is formed a strip of openbarrel connector means as illustrated in FIGURE 1 ready to be used inthe applicator mentioned hereinbefore.

The connector means described in conjunction with FIGURES 1 through 11can be used on various types of conductor means such as for example,conventional stranded or solid wire surrounded by an insulating sheet,film insulated wire, i.e., solid wire having a thin film of insulationtherearound such as for example Formvar (polyvinyl formal resin) orother suitable insulating material, or combinations of conventionallyinsulated con ductor means. FIGURES 12 and 13 illustrate connector meansCM crirnped onto conductor means 6 having a thin film of insulatingmaterial thereon. FIGURE 16 illustrates connector means CM crimped ontothe ends of conductor means 7 which is of the type having stranded wiressurrounded by an insulating sheath, and the connector means in FIGURE 17is crimped onto the ends of conductor means 6 and 7 to interconnectsame.

It is desirable when crimping the open barrel connector means of thepresent invention to use crimping dies of the type disclosed in US.Patent Nos. 2,600,012 and 2,818,632, which are assigned to the presentassignee. In use, the connector means are fed or placed within thecrimping area of the crimping dies, the conductor means being placedwithin the connector means. The crimping die of the crimping dies isoperated causing the free ends of the connector means to be foldedinwardly and downwardly toward the bottom of the connector means asillustrated in FIGURES 12 through 17 with each free end of the connectormeans circling or attempting to circle around the respective conductormeans as illustrated in FIGURES 12 through 14 and 17. During thecrimping operation of the connector means by the die members, thecrimping pressure during a large portion of the crimping operation is onthe rib members with the greatest amount of crimping pressure located atthe center of the connector means, the crimping pressure decreasing fromthe center of the connector means outwardly toward each end thereof.Thus, at the outer ends of the connector means, i.e., where no ribmembers are located, the crimping pressure does not exceed thecompressive strength of the insulation material; however, at the centerof the connector means or the area where the rib members are located,the crimping pressure is many times the allowable compressive strengthof the insulation material, but this high crimping pressure does notrupture the insulation material in this area because the resultantcrimping pressure is restrained longitudinally along the connector meansby friction between the crimping dies and the connector means whichprevents the insulation material from being impaired during the crimpingoperation.

Due to the fact that friction is an essential ingredient which preventsimpairment of the insulation material during the crimping operation, thesurface finish and fit of the dies must be correct and the surfaces ofthe connector means and dies must be substantially free of foreignmaterial in order to perform most satisfactorily. The length of theconnector means is dependent upon the abovementioned parameters and itsown cross section.

ince the metallic member of the connector means is elongated during thecrimping operation and since the insulation material is laminated, it isbelieved that the metallic member and the sheets of the laminatedmaterial undergo laminar flow thereby obviating rupture of the insulatedmaterial during the crimping operation.

In the case of film insulated wire in FIGURES 12 and 13, the top edgesof the rib members other than the rounded rib members are sharp therebyallowing the rib members to shear through the insulation during crimpingthus permittin contact between the conductive portion and the sides ofthe rib members. In the case of rounded rib members, these conductormeans undergo elongation during the crimping operation causing the thinfilm of insulation on the conductor means to open in the areas of therib members thereby allowing the rounded top rib members to engage theconductive portions of the con ductor means as illustrated in FIGURE 15.In between the rib members, the insulation on the conductor meansremains intact as illustrated in FIGURE 14. This is also true withrespect to the portions of metallic member 3 from the outermost ribs tothe ends thereof. An impoltant feature of the present invention is thefact that insulation material 2 extends beyond the corresponding ends ofmetallic member 3 and the area of engagement along the insulationmaterial Where the free ends are folded inwardly thereby providing aninsulated connection that more than adequately insulates the connection.

In terminating conductor means 7 in FIGURE 16, the non-striped ends ofthese conductor means are abutted in a Central location of the connectormeans then the connector means is crimped in the same manner as that ofFIGURES l2 and 13 thereby causing conductor means 7 to be electricallyspliced togethervia connector means CM. Rib members 4 penetrate throughthe insulating sheaths of conductor means 7 and they electrically engagea conductive portion thereof in the same manner that the rib membersengage the conductive portions of corn ductive means 6 in FIGURES l2 and13. The engagement of the rib members with the conductive portion ofconductor means 7 is illustrated in FIGURE 21. Between the rib members,the metallic member of the connector means engages the insulatingsheaths of conductor means 7 in the same manner as that illustrated inFIGURE 14. FIGURE 17 merely illustrates the fact that conductor means 6and 7 can be interconnected via connector means CM with the connectormeans engaging the conductive portions of conductor means 6 and 7 in thesame manner as that illustrated in FIGURES 12 through 16. FIG- URE 18illustrates the free ends of the connector means being bent back uponthemselves which occasionally happens mainly because of the size of theWire; however, this does not prevent the connector means from beingeffectively crimped onto the conductor means to form an excellentmechanical and electrical connection.

Some of the advantages of using the connector means of the presentinvention are as follows:

Crimp height control problems are reduced, crimping pressure requirementis less, more economical, longer applicator tooling and die life,crimping dies are of simplified construction and are not complicated andexisting die designs can be utilized, conductor means need not bestripped prior to terminating, retention of connector means on theconductor means does not depend upon plastic under acompressiveload,solid or stranded wire can be terminated, a controlled pressure gradientin the crimp allows crimping so that the Wire barrel may be deformedthrough insulation material without damaging the insulation material.Thus, as can be discerned, the connector means of the present inventionhas a number of advantages that render the connector means highlydesirable.

FIGURES 19 through 22 illustrate an embodiment of the connector meanswhich is similar to that illustrated in FIGURE 2 except that a ringtongue 8 or some similar means for connecting the connector means to amounting post or other connector means extends outwardly from metallicmember 3 and beyond one end of insulation material 2. Rib members 4preferably take the form illustrated in FIGURE 22 in that the two ribmembers closest to ring tongue 8 are of the same height and the otherrib members decrease in height. The tallest rib members are forpenetrating through the insulating sheath and engaging the conductiveportion of conductor means 7 while the other rib members penetrate intothe insulating sheath for engagement therewith so as to provide a strainrelief between the conductor means and connector means. FIGURE 21 showsa cross section through one of the rib members and in engagement withthe conductive portion of the conductor means. FIGURE 21a illustrates across section of the connector means when the rib members do not extendto the ends of the sides of the metallic mem ber. FIGURE 23 illustratesan embodiment of the connector means of FIGURES 19 through 22 in thatrib member 9 closest to ring tongue 8 is higher than any of the otherrib members and constitutes a shearing rib member so that upon thecrimping dies reaching the end of their crimping position, they are heldin this position for a short period of time and a minimal force isapplied to the conductor means being illustrated as 7 over n'ng tongue 8thereby severing the conductor means at this point from the portion ofthe conductor means crimped onto the connector means. This isaccomplished by shearing rib member 9 almost shearing the conductormeans through at this point thereby obviating having to cut or strip theconductor means in the area where the conductor means is to beterminated onto the connector means. This feature can also be applied tothe connector means of FIGURES 118.

FIGURES 24 through 29 illustrate a further embodiment of the presentinvention which is directed to a coaxial connector means CCM and moreparticularly to coaxial connector means of the phonoplug variety. Thecoaxial connector means in this embodiment comprises a U-shaped barrelmember 10 having spaced rib members 11 extending outwardly from theinterior surface. As can be discerned, rib members 11 are of varyingheights from the outermost rib member to the innermost rib member; thetop of each rib member defines a sharp edge. A stop member 12 extendsoutwardly from the bottom surface of barrel member 10 and slots 13 aredisposed in the forward portion of barrel member 10. The thickness ofbarrel member 1i) from stop member 12 to the outer end is about fourtimes the thickness of the portion of the barrel member containing slots13, because the portion carrying the rib members is preferably thickerto allow proper crimping to be obtained while the thinner portion has tohave spring characteristics. An insulator 14 is disposed in barrelmember 10 between stop member 12 and an adjacent rib member; slot 15 isdisposed in insulator 14. Insulator 14 is made of yielda'ble plasticmaterial and the inner part of slot 15 is substantially circular.

A center contact 16 is hollow and has one end defining a roundedconfiguration while the other end has lugs 17 extending outwardlytherefrom. The lugged end of center contact 15 is disposed Within slot15 of insulator 14 as illustrated in FIGURES 24, 25, and 27. Thus,center contact 16 is placed within slot 15 of insulator 14 and theinsulator is placed within barrel member 10 against stop member 12.Insulator 14 is slightly larger than barrel member 19 so that theinsulator fits snugly within the barrel member thereby maintaining theinsulator and center contact 16 within the barrel member.

A coaxial cable means 18 is stripped so as to expose only a suitablelength of center conductor 19 as illustrated in FIGURES 24 and 25. Thecoaxial cable means is placed within barrel member 10 and intoengagement with insulator 14 and the lugged portion of center contact 16so that center conductor 19 is disposed within the lugged portionthereof as illustrated in FIGURE 25. The coaxial connector means withthe coaxial cable means in place therein is then placed within suitablecrimping dies (not shown). The crimping dies are operated to crimp thecoaxial connector means onto the coaxial cable means thereby forming acrimped connection having a substantially O-configuration as illustratedin FIGURE 26..

During the crimping operation, barrel member It) is compressed aroundthe coaxial cable means and insulator 14 causing rib members 11 topenetrate outer insulation 22. with the highest rib members engagingouter conductor 20 and the shortest rib members penetrating just intothe outer insulation so as to form a strain relief between the coaxialcable means and the coaxial connector means. Center conductor 19 andinner insulation 21 supplies suflicient backup support to allow thecrimp to be performed. The action of crimping is transmitted throughinsulator 14 which crimps the lugged portion of center contact 16 ontocenter conductor 19 as illustrated in FIG- URES 28 and 29. Thus, theembodiment of FIGURES 24 through 29 discloses a unique coaxial connectormeans that is crimpable onto coaxial cable means and stripping of thecoaxial cable means to expose the center conductor is all the strippingoperation that has to be performed.

While metallic member 3 and barrel member 19 have been disclosed asbeing U-shaped in configuration, it is obvious that they may take anysuitable form and that crimping dies are to be used that will performthe desired crimping operation.

The present invention is useful in terminating conductor means that usesaluminum as the conductive portion. The present invention can be used inconjunction with conductor means whereby the conductive portion has beenexposed via a stripping operation and, instead of ribs, these can bereplaced by a thicker disposition of material in the crimping area ofthe connector means which would allow the crimping operation to be performed without rupturing or damaging the insulation material in theconnector means and this is especially directed to the embodiments ofFIGURES 2 and 19 on stripped conductor means. More than two conductormeans can be terminated when using the connector means of FIGURE 2 andthe free ends of the conductor means will evenly engage the conductormeans. Extensions can be disposed on the free ends of the connectormeans of FIGURES 2 and 19 so as to extend outwardly from the sides Wherethe rib members are located, because if more metal is provided in thecentral area of the metallic member, then this is the point of greatestpressure and at which the insulation material can support itself.Tapering of the metallic member to match the pressure gradient of thecrimp allows the deformation of the metallic member through theinsulation material Without damaging the insulation material which has alower yield than the metallic member.

As can be discerned, there has been disclosed a unique connector meansfor terminating insulating conductor means as well as a unique coaxialconnector means for terminating coaxial cable means.

It will, therefore, be appreciated that the aforementioned and otherdesirable objects have been achieved; however, it should be emphasizedthat the particular embodiments of the invention which are shown anddescribed herein, are intended as merely illustrative and not asrestrictive of the invention.

What is claimed is: r

1. An electrical connector comprising an open-barrel ferrule memberhaving an interior surface extending generally throughout the ferrulemember, a series of rib members extending outwardly from said interiorsurface of said ferrule member and extending transversely with respectto the longitudinal axis thereof, said rib members being disposed alongan area of said ferrule member, said area being spaced inwardly fromeach end of said ferrule member extending along about one-half thelength thereof, and insulation means on an exterior surface of saidferrule member and extending entirely thereover.

Z. An electrical connector according to claim 1 wherein said rib membersare equally spaced from one another.

3. An electrical connector according to claim 1 wherein said rib membershave the same cross-sectional configuration.

4. An electrical connector according to claim 1 wherein some of said ribmembers have a cross-sectional configuration different from the otherrib members.

5. An electrical connector according to claim 1 Wherein said rib membershave the same height.

6. An electrical connector according to claim 1 wherein said rib membershave varying heights.

7. An electrical connector according to claim 1 wherein said insulationmeans is laminated.

8. In a connector means, a ferrule member having an interior surfaceextending generally throughout the ferrule member, rib members extendingoutwardly from said interior surface of said ferrule member transverselyto a longitudinal axis thereof, said rib members being equally spacedfrom each other along substantially an equal area of a central part ofsaid ferrule member, said area being spaced inwardly from ends of saidferrule member, and laminated insulation means on an exterior surface ofsaid ferrule member.

9. An electrical connector crimpable onto insulated conductor meanscomprising an open barrel ferrule member having an interior surfaceextending generally throughout the ferrule member, rib means extendingoutwardly from said interior surface surface of said ferrule member andextending along about half the length thereof within a central portionthereof, said rib means extending transversely to a longitudinal axis ofsaid ferrule member for penetrating insulation on said conductor meansand electrically engaging the conductive portion thereof upon saidferrule member being crimped onto said conductor means, and insulationmeans on said ferrule member, said ferrule member being crimped throughsaid insulation means onto said conductor means without impairing theinsulation properties of said insulation means.

10. An electrical connector crimpable onto insulated conductor meanscomprising an open barrel ferrule member having an interior surfaceextending generally throughout the ferrule member, rib means extendingoutwardly from said interior surface of said ferrule member andextending along about half the length thereof within a central portionthereof, said rib means extending transversely to a longitudinal axis ofsaid ferrule member, some of said rib means penetrating insulation onsaid conductor means and electrically engaging the conductive portionthereof while the other rib means penetrate the insulation withoutengaging the conductive portion to provide a strain relief between theconnector and conductor means upon said ferrule member being crimpedonto said conductor means, and insulation means on said ferrule member,said ferrule member being crimped through said insulation means ontosaid conductor means without impairing the insulation properties of saidinsulation means.

11. An electrical connector according to claim 10 wherein said ferrulemember includes a shearing rib means positioned at an end of saidferrule member opposite from the end where the insulated conductor meansextends outwardly from said ferrule member, said shearing rib meansbeing of greater height than the other rib means so that upon crimpingof said ferrule member onto said conductor means, said shearing ribmeans severs said conductor means.

12. A blank for making an electrical connector including as aferrule-forming section a substantially rectangular piece of metalhaving an interior surface and a middle section and outer sections oneach side of said middle section, said interior surface extendinggenerally throughout said piece of metal, the combined length of saidouter sections being of substantially the same length as said middlesection, and a series of parallel ribs extending out from said interiorsurface along said middle section.

13. An electrical connector comprising a generally U- shaped ferrulemember having an interior surface and a middle section and outersections on each side of said middle section, said interior surfaceextending generally throughout said ferrule member, said middle sectionhaving a length substantially equal to a combined length of said outersections, a series of parallel ribs extending outwardly from saidinterior surface along said middle section toward a longitudinal axis ofsaid ferrule member, and insulation means in engagement With an exteriorsurface of said ferrule member and extending outwardly beyond the freeends of said ferrule member and the outer sections.

References Cited UNITED STATES PATENTS 2,434,475 1/1948 Sullivan 339-11.2,674,725 4/1954 Buchanan 339-27l 2,783,447 2/1957 Watts 339-9'2,800,638 7/1957 Hammell 339-27l 3,048,650 8/1962 Allen et al.

3,156,514 11/1964 Wing et al 3399',

10 MARVIN A. CHAMPION, Primary Examiner.

EDWARD C. ALLEN, Examiner.

J. H. MCGLYN N, Assistant Examiner.

1. AN ELECTRICAL CONNECTOR COMPRISING AN OPEN-BARREL FERRULE MEMBERHAVING AN INTERIOR SURFACE EXTENDING GENERALLY THROUGHOUT THE FERRULEMEMBER, A SERIES OF RIB MEMBERS EXTENDING OUTWARDLY FROM SAID INTERIORSURFACE OF SAID FERRULE MEMBER AND EXTENDING TRANSVERSELY WITH RESPECTTO THE LONGITUDINAL AXIS THEREOF, SAID RIB MEMBERS BEING DISPOSED ALONGAN AREA OF SAID FEMILE MEMBER, SAID AREA BEING SPACED INWARDLY FROM EACHEND OF SAID FERRULE MEMBER EXTENDING ALONG ABOUT ONE-HALF THE LENGTHTHEREOF, AND INSULATION MEANS ON AN EXTERIOR SURFACE OF SAID FERRULEMEMBER AND EXTENDING ENTIRELY THEREOVER.